An attendee holds a campaign sign in support of Senator Bernie Sanders in Tampa, Florida, on March 10, 2016.

Photographer: Andrew Harrer/Bloomberg

Ohio must let 17-year-olds vote in the state’s March 15 primary, if they turn 18 by Election Day, a judge ruled in a boost to Bernie Sanders.

Sanders’s surprise win over Hillary Clinton in the Michigan primary this week was driven in part by his popularity with younger voters, many of whom are attracted to his call for an economic revolution against the wealthy elite. Sanders got the support of 81 percent of 18- to 29-year-olds in the Michigan primary, according to CNN’s exit polls.

Ohio Secretary of State Jon Husted, a Republican, reinterpreted a decades-old law by describing the primary as an election of delegates, rather than a nomination. Ohio doesn’t let voters under 18 directly elect people, Husted said.

That was a misinterpretation of the law, Franklin County Court Judge Richard A. Frye said in a ruling Friday.

“The secretary has a clear legal duty to promptly advise all 88 county Boards of Election to disregard his previous interpretation” of the law, Frye said. The complaint was filed by students and the Fair Elections Legal Network. It wasn’t affiliated with any candidate or political party.

A federal judge in Columbus, Ohio, earlier on Friday declined to rule in a parallel case filed by Sanders until after the state court judge ruled. While Sanders wasn’t involved in the state court case, both suits made the same argument.

‘Huge Victory’

“This is a huge victory for 17-year-olds across Ohio. Their votes for presidential nominees will now count when they vote on either Tuesday or over the weekend in early voting,” Brad Deutsch, attorney for the Sanders campaign, said in a statement.

Ohio, a key general election swing state, is among about two dozen states that allow threshold voters to cast primary ballots to increase turnout among young adults. Ohio’s law was passed in 1981, allowing 17-year-olds to vote in all the recent primaries, Sanders said in his complaint.

“The students are really excited that their vote will be able to count,” Rachel Bloomekatz, the teenagers’ lawyer, said in a phone interview.

Sanders argues the Ohio age restriction will have a greater impact on minority voters who make up a larger percentage of younger voters. He also says that voters who participate in the primary are more likely to turn out on Election Day.

Husted’s predecessor, Democrat Jennifer Brunner, advertised the law heavily to young people with a campaign called “Vote at 17,” according to the compliant. And ex-Ohio State Senator Nina Turner, a Democrat who ran against Husted for secretary of state, said in a statement that Ohio law is clear that 17-year-olds may vote in presidential primaries.

Limiting Turnout

Groups aligned with Democrats are fighting court battles in several states to turn back what they say are Republican attempts to hinder voter turnout by minorities and young people who lean Democratic. The effort has focused on swing states.

In North Carolina, minority voters went to trial to overturn a strict voter restriction law. In Alabama, a federal judge is weighing the state’s request to dismiss a lawsuit filed in December by an NAACP chapter over a 2014 voter-ID law. The judge in February rejected the group’s bid for an injunction. In Virginia, a trial over that state’s voter-ID law ended this month.